Neural oscillations and synchronization differentially support evidence accumulation in perceptual and 
value-based decision making

Rafael Polanía
Laboratory for Social and Neural Systems Research, University of Zurich

Organisms make two types of decisions on a regular basis. Perceptual decisions are determined by 
objective states of the world (e.g., melons are bigger than apples), whereas value-based decisions are 
determined by subjective preferences (e.g., I prefer apples to melons). Theoretical accounts suggest that 
both types of choice involve neural computations accumulating evidence for the choice alternatives; 
however, little is known about the overlap or differences in the processes underlying perceptual vs. 
value-based decisions. We analyzed EEG recordings during a novel paradigm where perceptual- and 
value-based choices were based on identical stimuli. For both types of choice, evidence accumulation 
was evident in parietal gamma-frequency oscillations, whereas a similar frontal signal was unique for 
value-based decisions. Fronto-parietal synchronization of these signals predicted value-based choice 
accuracy. The results of this investigation bolster the notion that decisions emerge from an integrative 
evidence accumulation process that occurs in parallel across distinct brain regions that process different 
aspects of the incoming sensory signals (e.g., perceptual and value readout). This process appears to be 
instantiated locally by neural oscillations and seems to be coordinated between different areas via large-
scale neural synchronization, respectively.